title: Stabilization of microtubules by GTP analogues.
abstract: We recently demonstrated that the nonhydrolyzable analogues of GTP (GMPPCP and GMPPNP) and ATP support the elongation phase of tubulin assembly and are incorporated into the E-site of polymerized tubulin. In this report we studied the stability of microtubules containing GTP analogues by examining length redistributions after shearing at polymer steady state. The mean length of a population of microtubules containing GMPPCP increased only by 37% over a 150 min time period after shearing. Microtubules which contained 70% ATP and 30% GDP at the E-site increased in length by 88%. In contrast, the mean length of microtubules assembled in the presence of GTP increased by 410% in the same time period. These results suggest that microtubules containing GMPPCP or ATP at their ends are stabilized from depolymerization.
authors.affiliation: Department of Biochemistry, University of Kansas, Lawrence 66045-2106.
authors.forename: M R
authors.initials: MR
authors.lastname: Mejillano
authors.forename: J S
authors.initials: JS
authors.lastname: Barton
authors.forename: R H
authors.initials: RH
authors.lastname: Himes
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002417:Cattle; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000502:physiology*; D066298:In Vitro Techniques; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D011485:Protein Binding; D014404:Tubulin / Q000502:physiology*
chemical_list: D014404:Tubulin; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate